The present invention pertains to construction components which may be locked together in various configurations to form structures such as bridges, platforms, and the like. Prior U.S. Pat. No. 2,876,726, U.S. Pat. No. 3,057,315, and U.S. Pat. No. 3,805,721 describe a series of successive developments in such construction components and special locks therefor. The present invention provides further improvements in such construction components. However, while the inventions of said prior patents are described in the context of buoyant construction components, such as are used to form barges, floating platforms, floating bridges, and the like, it is contemplated that the present invention may be applied not only to such buoyant components but also to components for forming non-floating structures such as earth supported bridges, earth supported platforms, etc.
In modern international commerce, there is widespread use of what are termed "standard freight containers." Such a container is generally in the form of a rectangular parallelepiped. It not only has standardized external dimensions, but in addition, usually includes a standard form of fitting which may be engaged by standardized tools and the like for both lifting and moving the container, and for lashing it in place in various locations. Freight handling facilities, e.g. at seaports, throughout the world, have been equipped with such standardized lifting and moving equipment, whereas freight vehicles, such as ships, have been equipped with standard sized racks used in aligning and retaining such containers. Such standardization, on an international scale, has vastly facilitated the shipping and handling of many types of freight which can be packed in the containers.
Coinciding with the above developments in freight handling equipment and practices, is the need for transporting construction components of the type generally exemplified by the aforementioned prior U.S. patents to the locations at which they will be used. Such transport could be greatly facilitated and the cost thereof reduced if the construction components could be handled and shipped in the same manner as standard freight containers.
The generally rectangular parallelepiped configuration of such components would readily lend itself to such handling, but problems are presented by the fact that the lock assemblies carried by the components include protruding pin members. Thus, for example, if the gross dimensions of such a component, measured between the outer surfaces of its walls, were sized to correspond to those of a standard freight container, the pins of the lock assemblies would protrude beyond such standardized profile or gross dimensions, and thereby prevent the component from being placed in the standardized racks typically provided on freighters. On the other hand, if the construction component were sized so that its dimensions, measured to the outer ends of the lock pins, would correspond to those of a standard freight container, the gross dimensions, measured between the outer surfaces of the walls, would then be too small to enable the component to be properly held in such racks.
Furthermore, even if the components are not to be handled or shipped as standard freight containers, it would be preferable to eliminate the protruding pins in any transport or storage situation, not only for the most economic use of space, but also for the protection of the pins themselves and other structures, apparatus, or even personnel which the pins might strike in the course of handling.
Another area for potential improvement revolves around the fact that, when such construction components are locked together to form a given structure, many different types of loads may be imposed thereon. For example, where the components are assembled to form a floating structure, one of the greatest forces is a vertical shear-type force exerted by virtue of the fact that one component tends to rise or fall with respect to another due, for example, to wave action and/or to the passage of motor vehicles from one component to the next across the upper surface of the overall structure. Another significant type of force is a horizontally directed tensile force exerted by virtue of the tendency of the connected components to separate. There are also transverse horizontal shear-type forces, which generally represent a somewhat less serious problem than the transverse vertical shear forces.
In the structures disclosed in the aforementioned prior U.S. patents, when two components are locked together, the transfer of all of these various forces from one component to the next involves the pin members of the male lock assemblies. Thus, the dimensions of these pin members are a limiting factor on the magnitude of forces which can be handled. The ramifications of this limitation in turn include not only limits on the uses to which such components can be put, but also limits on the size of the components themselves, given a specific pin size.
Yet another area for potential improvement relates to the fact that, in many situations, it is desirable, or even necessary, that the workers who assemble the construction components to form a completed structure stand on those very comonents as they are being connected together. When the components are buoyant, and are connected together while floating on a body of water, the proglems are further complicated. Thus, it is extremely important that the lock systems be easy to use, requiring only a few simple motions with simple hand tools. In general, the aforementioned U.S. Pat. No. 2,876,726, U.S. Pat. No. 3,057,315, and U.S. Pat. No. 3,805,721 meet these needs quite well. However, when the workers stand, as they naturally would, near the component wall at which the connections are to be made, and if the components are floating, then the components tend to rock or tip downwardly at said adjacent walls, which tends to splay the lower edges of said walls making it difficult to mate the connectors along said lower edges.
There have been attempts to address the various problems discussed above, but they have not been completely satisfactory. In particular, there have been suggestions that pontoons or the like could be sized to generally correspond to standard freight containers. These devices have been designed with locks substantially different from the type described and illustrated in the aforementioned prior U.S. patents.
German Patent Publications No. 2725060 and No. 2651247 are exemplary. The lock structures illustrated therein do not employ horizontally extending pin members carried by the components to be connected. Rather, the components must be brought together so that recesses in the two components are properly aligned, and then a separate pin member is inserted into the aligned recesses in a vertical directional mode, the pin member and recesses being configured so as to effect connection of the two components.
This system suffers from several disadvantages. First, in what may have been an effort to devise a locking arrangement which would not include parts protruding substantially beyond the gross dimensions of the structural component, a form of locking system has been chosen which differs substantially from the type of lock generally described and illustrated in prior U.S. Pat. No. 2,876,726, U.S. Pat. No. 3,057,315 and U.S. Pat. No. 3,805,721. This is undesirable because the general type of lock disclosed in said prior U.S. patents has proven, over many years of use, to be particularly effective, reliable, easy to use, and otherwise highly successful in the connection of construction components, particularly for floating structures, for which use this last-mentioned locking scheme was specially developed. It is undesirable to sacrifice these proven and highly successful features of the locks exemplified by the prior U.S. patents by going to the less effecting locking scheme exemplified by the aforementioned German patent publications.
Another problem with the type of structure exemplified by the German patent publications is that the locking system requires a completely separate insertable pin member. These pin members must be separately carried and stored, and therefore they are susceptible to being lost, misappropriated by workers for use as make-shift tools, or otherwise disposed of so that, when the time comes to connect the structural components to form a structure, the pin members either cannot be located, or have been damaged.
Still another problem with this type of prior art scheme is that, due to the elimination of any part which extends a substantial distance horizontally from the side walls of the construction component, there is no effective structural guidance for bringing two such components into proper alignment, and maintaining them so aligned, so that the pin member can be inserted into the aligned recesses in order to complete the lock. This can be a particular problem when it is necessary to connect such components while they are floating on a body of water.
In some instances, structures somewhat similar to those disclosed in the German patent publications have further been provided with mating lugs and recesses projecting and receiving in a generally horizontal direction, but by a distance small enough not to interfere with the handling of the structural component in the manner of a standard freight container. Because of this very limited horizontal extent, these lugs and recesses do not really provide a great deal of assistance with the alignment problem described above. In short, the components must be fairly closely aligned before the lugs and recesses can be engaged. It is believed that such lugs and recesses probably were not provided primarily to serve as guides in aligning the components, but rather, may have been provided to bear the shear loads between the components, since the vertically arranged pin and recess scheme does not include any means for doing so.
Still another scheme for connecting pontoons is disclosed, in various embodiments, in the following U.S. patents: U.S. Pat. No. 3,799,100; U.S. Pat. No. No. 3,818,854; U.S. Pat. No. 3,822,667; U.S. Pat. No. 3,938,461; and U.S. Pat. No. 4,290,382. The last-mentioned patent generally corresponds to at least one known commercial embodiment of such scheme. One of the main features of this scheme is that it is specifically designed to provide a hinging-type action or articulation between the connected pontoons about a horizontal axis. All of the connectors on a given side of the pontoon are horizontally aligned on the same level. Furthermore, as best shown in the first four patents listed above, the pin members of the locks have flexible elastomeric sections bridging gaps between adjacent pontoons to allow for such articulation. The last listed patent, U.S. Pat. No. 4,290,382, further discloses the provision of separate shear bearing formations. These formations define generally cylindrical shear bearing surfaces, with the axes of the cylinders disposed horizontally and aligned with the pin-type connectors so as to form large hinges.
This type of connection scheme, and the hinging action specifically provided thereby, are unacceptable in construction components for forming such structures as bridges, drilling platforms, etc. Furthermore, the connectors are so large and unwieldly that they cannot be manually moved, even with hand tools, but rather, require the use of large, heavy duty power tools such as motorized winches. Likewise, the extremely large connector elements, e.g. the shear bearing formations which protrude substantially from the sides of the pontoons, effectively eliminate the possibility of sizing and handling the pontoons as standard freight containers.